Oxidation and Reduction in Terms of Electrons

The word Redox comes from the first letters of the two processes that occur side-by-side;

  • Reduction
  • Oxidation

In a redox reaction, both oxidation and reduction take place. We can analyse them by studying the transfer of electrons.

Oxidation depicted by one circle labelled A gaining a positive charge, and a circle labelled B gaining a negative charge.

  • Reduction is the process of gaining electrons
  • Oxidation is the process of losing electrons

It’s important to note that in a chemical reaction, electrons are neither created nor destroyed. They are only transferred between atoms.

One way to remember the difference between oxidation and reduction is through the acronym “OIL RIG.” “Oxidation Is Loss” (OIL) means the loss of electrons, while “Reduction Is Gain” (RIG) means the gain of electrons.

Let’s look at an example of a balanced ionic equation that involves magnesium and chlorine:

Magnesium + Chlorine Magnesium Chloride

Mg + Cl2 → MgCl2

As shown in the equation, one molecule of magnesium chloride consists of one Mg²⁺ ion and two Cl⁻ ions. We can split the reaction into two parts to show oxidation and reduction taking place.

Mg Mg²⁺ + 2e⁻

  • The magnesium atoms are oxidised as they lose electrons.

Cl2 + 2e⁻ 2Cl⁻

  • The chlorine atoms are reduced as they gain electrons.

Displacement reactions are another example of redox reactions, where one element is displaced by another in a compound.